On August 7, 2025, the New Zealand Environmental Protection Authority (EPA) proposed a full ban on chlorthal-dimethyl (DCPA) as part of its reassessment process and opened a public consultation period until October 6, 2025. 

Background 

• DCPA is a pre-emergence herbicide used to control wireweed. 

• In 2024, NZ EPA imposed restrictions on DCPA due to concerns over its impact on fetal development. 

• The chemical is already banned in Australia, Canada, the EU, and the U.S., where the U.S. EPA had previously issued an emergency suspension order. 

Key Health and Environmental Concerns 

• High-risk groups: pregnant bystanders, pregnant workers, and individuals entering treated fields. 

• Health risks: endocrine disruption and potential developmental effects, including low birth weight, impaired brain development, and motor function deficits. 

• Environmental risks: groundwater contamination. 

• Even with strict protective measures (respirators, gloves), risks cannot be adequately controlled. 

Usage in New Zealand 

• Agricultural use is already limited. 

• Around two-thirds of growers have switched to cheaper and more accessible alternatives. 

EPA Assessment & Conclusion 

Following a detailed review under the Hazardous Substances and New Organisms Act 1996 (HSNO Act), the EPA concluded that: 

• Health risks to pregnant women cannot be mitigated. 

• Groundwater contamination risks remain unresolved. 

• Current use is limited. 

• Safer, cost-effective alternatives are available. 

Proposed Outcome 

• Revocation of all approvals for herbicides containing DCPA under the HSNO Act. 

• Ban on import, manufacture, and use in New Zealand. 

• A six-month grace period will be allowed for safe disposal of existing stocks. 

Stay ahead in sustainability compliance with Global PCCS —where expert insights meet the latest regulations. Unlock a future where compliance fuels sustainability, helping your business thrive in a greener, well-regulated world. For more information, contact us at info@globalpccs.com